The Joint USAF/NOAA Report of Solar and Geophysical Activity, issued on November 9, 2006, provides a comprehensive analysis of solar and geomagnetic conditions observed between November 8, 2100 UTC, and November 9, 2100 UTC. This report, prepared jointly by the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) Space Environment Center and the U.S. Air Force, is part of a series of daily bulletins that monitor and forecast space weather phenomena. ([](

Solar Activity Analysis

During the specified period, solar activity was classified as very low. The primary focus was on Region 923, located at S06E58, which produced several B-class flares. These flares are considered minor in intensity and are common during periods of low solar activity. Region 921, situated at S06W78, was in a state of decay and did not contribute any significant activity during this timeframe. ([](

Solar Activity Forecast

The forecast for solar activity indicated a continuation of low levels. There was a slight chance for an isolated M-class flare from Region 923. M-class flares are moderate in intensity and can have brief effects on radio communications and navigation systems. However, the likelihood of such events was minimal during this period. ([](

Geomagnetic Activity Summary

The geomagnetic field during this period was characterized as quiet to unsettled. Solar wind speeds increased steadily throughout the day, reaching approximately 400 km/s by the time of the report's issuance. This increase was attributed to a recurrent coronal hole moving into a geoeffective position. The interplanetary magnetic field (IMF) strength also rose to about 20 nT, with the Bz component varying between +/- 10 nT. These conditions contributed to the observed geomagnetic activity levels. ([](

Geomagnetic Activity Forecast

The forecast for geomagnetic activity anticipated unsettled to active conditions, with a chance for isolated minor storm periods on November 10 due to the coronal hole high-speed stream. Quiet to unsettled conditions were expected on November 11-12. Geomagnetic storms can impact satellite operations, communication systems, and power grids, making such forecasts crucial for preparedness. ([](

Event Probabilities and Indices

The report provided specific probabilities for various solar and geomagnetic events over the subsequent days:

  • Class M Flares: 10% chance on November 10, 10% on November 11, and 10% on November 12.
  • Class X Flares: 1% chance on each of the three days.
  • Proton Events: 1% chance on each of the three days.
  • Penticton 10.7 cm Flux: Observed at 89, with predicted values of 90 for November 10, 85 for November 11, and 85 for November 12. The 90-day mean was 78. ([](

Additionally, the geomagnetic A indices, which measure the level of geomagnetic activity, were reported as follows:

  • Observed Afr/Ap on November 8: 0/1
  • Estimated Afr/Ap on November 9: 8/8
  • Predicted Afr/Ap for November 10-12: 10/20, 7/10, and 5/8, respectively. ([](

Geophysical Activity Probabilities

The report also detailed the probabilities of various levels of geomagnetic activity for the upcoming days:

Middle Latitudes

  • Active: 25% on November 10, 15% on November 11, and 15% on November 12.
  • Minor Storm: 10% on November 10, 5% on November 11, and 1% on November 12.
  • Major-Severe Storm: 1% on each of the three days. ([](

High Latitudes

  • Active: 40% on November 10, 25% on November 11, and 20% on November 12.
  • Minor Storm: 25% on November 10, 11% on November 11, and 11% on November 12.
  • Major-Severe Storm: 10% on November 10, 5% on November 11, and 5% on November 12. ([](

Conclusion

The Joint USAF/NOAA Report of Solar and Geophysical Activity for November 9, 2006, provided a detailed analysis of the solar and geomagnetic conditions during the specified period. The report highlighted very low solar activity, with a slight chance for isolated M-class flares, and quiet to unsettled geomagnetic conditions influenced by a recurrent coronal hole. Such reports are essential for understanding space weather dynamics and their potential impacts on Earth-based technologies and infrastructure. ([](

Sources

  • Editor — Joint USAF/NOAA Report of Solar and Geophysical Activity 09 Nov 2006 —